Heat exchanger support structure

ABSTRACT

The present invention relates to a heat exchanger of the type involving a nest of tubes formed from concentric layers of wound pipes, in which the pipes in each layer are attached, generally near their ends, by being fitted between two successive crowns in a series of crowns, with the inside edge of one crown extending round the outside edge of the crown it fits on to, so as to form a plate reaching out transversally from the core. The pipes in each of the wound layers preferably rest in the concave sections of ridged uprights laid lengthwise along the core, and fitted between each pair of layers, or between the first layer of pipes and the core, the said ridged uprights being attached at their ends to the crowns holding the ends of the pipes. These measures provide a rigid structure, in which the tubes are firmly held in position with respect to the core of the exchanger.

United States Patent Bosquain et al.

[ 1 Oct. 24, 1972 [54] HEAT EXCHANGER SUPPORT STRUCTURE [72] Inventors: Maurice Bosquain, Paris; Marcel Bourjot, La-Varenne-Saint-Maur; Maurice Kirsch, Champigny-sur Marne, all of France [73] Assignee: LAir Liquide, Societe Anonyme pour LEtude et LExploitation des Procedes Georges Claude, Paris, France [22] Filed: July 28, 1970 [21] Appl. No.: 58,777

[30] Foreign Application Priority Data Nov. 13, 1969 France ..69 38 976 July 9, 1970 France ..7023900 [52] US. Cl. ..165/145, 165/163, 122/32 [51] Int. Cl. ..F28f 9/22 [58] Field of Search ..165/145, 163; 122/32, 34, 250, 122/510 [56] References Cited UNITED STATES PATENTS 3,228,463 l/l966 Kagi ..165/163 X 3,348,610 10/1967 Vollhardt ..122/34 X 2,847,192 8/1958 Smith et al ..165/162 X 3,256,932 6/1966 Schlichting ..165/ 163 3,055,641 9/1962 Miller.... ..165/145 X 3,302,620 2/1967 Menzel ..122/32 X 3,509,939 5/1970 Weber ..l65/l63 X 3,482,625 12/1969 Bray ..165/163 X FOREIGN PATENTS OR APPLICATIONS 693,731 9/1964 Canada ..165/163 Primary Examiner-Frederick L. Matteson Assistant Examiner-W. C. Anderson Attorney-Young & Thompson [5 7] ABSTRACT The present invention relates to a heat exchanger of the type involving a nest of tubes formed from concentric layers of wound pipes, in which the pipes in each layer are attached, generally near their ends, by being fitted between two successive crowns in a series of crowns, with the inside edge of one crown extending round the outside edge of the crown it fits on to, so as to form a plate reaching out transversally from the core. The pipes in each of the wound layers preferably rest in the concave sections of ridged uprights laid lengthwise along the core, and fitted between each pair of layers, or between the first layer of pipes and the core, the said ridged uprights being attached at their ends to the crowns holding the ends of the pipes.

These measures provide a rigid structure, in which the tubes are firmly held in position with respect to the core of the exchanger.

' 8 Claims, 5 Drawing Figures P'ATENTED BET 24 an SHEET 1 0F 4 1 HEAT EXCHANGER surronr srnuc'rurm The present invention relates to a heat exchanger of the type involving a nest of tubes formed from concentric layers of wound pipes or windings between a central core and an outer covering, means for distributing and collecting fluid at each end of the said nest of tubes, and means for the passage of a fluid lengthwise around the pipes. The pipes of said windings are generally held in position by pressing close together. One pipe may very easily slide in relation to the others, and settle as a result of different solicitations, generally proportional to the weight of the windings, during manufacturing, transportation, working, etc, of said exchangers. In any case the way in which such exchangers are assembled excludes the possibility of constructing very large ones, since the above-mentioned disadvantages then become quite unacceptable.

One object of the present invention is an exchanger so designed as to ensure that the nest of tubes cannot go out of shape subsequently. Another object of the invention is an exchanger of extensive exchange surface, with large dimensions, which can in particular be transported without risk of damage. Yet another object of the invention is an exchanger providing a rigid structure which leads to a better working.

According to one particular feature of the invention, the pipes in each layer are attached, generally near their ends, by being fitted between two successive crowns in a series of crowns, with the inside edge of one crown extending round the outside edge of the crown it fits on to, so as to form a plate reaching out transversally from the core. The pipes in each of the wound layers preferably rest in the concave sections of ridged uprights laid lengthwise along the core, and fitted between each pair of layers, or between the first layer of pipes and the core, the said ridged uprightsbeing attached at their ends to the crowns holding the ends of the pipes. These measures provide a rigid structure, in which the tubes are firmly held in position with respect to the core of the exchanger. In one recommended embodiment of the invention, at least one of the crown plates presses against radial arms fixed rigidly to the core, and if the core of the exchanger has a vertical axis, these supporting arms are attached rigidly to a lower supporting structure resting on the ground. To prevent the possibility of pressure losses in the interstitial spaces of the nest of tubes, tightness rings are placed between the pipes and the notches in the crowns into which they fit, and a deflection system isplaced, between the nest of tubes and the wall of the exchanger shell. This is to avoid the'passage of the interstitial fluid along the wall of the exchanger shell.

The description given below as an example will show more clearly the characteristics and advantages of the present invention, as well as the accompanying drawings referred to, in which:

FIG. 1 is a diagrammatic cross-section, taken vertically, of an exchanger according to the invention.

FIG. 2 is another diagrammatic view of this exchanger, with parts cut away.

FIG. 3 is a cross-section of the part of the exchanger near the core.

FIG. 4 is a view of part of the exchanger near the perimeter of the nest of tubes, partly in cross-section and partly with sections cut away.

FIG. 5 is a detailed view of the supporting structure of a plate.

According to these accompanying drawings, a wound exchanger consists of a core 1 made up of a cylindrical metal body 2, with end sections 3 and 4 at bottom and top respectively. A large number of pipes such as 10 are wound on this core, arranged between a distribution system at the top and a collection system at the bottom. The top distribution system consists of a sphere 13 into which lead a large number of pipes 10a, this sphere 13 being supplied with liquid through a tubular connecting piece 14; a collector 15 comprises a tubular plate from which a number of pipes 10b may lead out.

At the bottom, the collection system in the same way includes a collecting sphere 17 into which lead the pipes 10a, and which also includes a discharge pipe 18, as well as, possibly, a collector 19 with a tubular plate to which lead the pipes 10b.

The pipes 10a and 10b are wound in layers on the core as follows: each layer of pipes consists of pipes 10a and 10b resting on ridged uprights 21 in the form of metal strips in which projecting sections have been produced by stamping, so that between each pair of projections 22 a concave section 23 is provided, forming a space for a pipe 10. These ridged uprights 21 are positioned uniformly round the winding circumference and between each pair of layers of pipes, and they are attached at the upper end by a transverse plate 24, and at the lower end by a transverse plate 25. Each transverse plate 24 or 25 consists of a number of crowns 26, 26, etc, each formed from a center web or rib 27 and two flanges or wings 28 and 29, in such as way that an outer annular crown 26, provided with passages 30 and 31 in the center rib 27, can fit between the wings 28 and 29, which have some elasticity, of an inner crown 26. These annular crowns 26, 26, etc, contain three sets of perforations: perforations side by side forming notches 32 open to the outside, slightly wider than the diameter of a pipe 10; a number of perforations 33, into which the feed pipes or upward pipes 34 fit; and finally a large number of channels 35, forming a passage for the vapor phase of the interstitial fluid.

The pipes 10 are fitted into the notches 32 and substantially hermetically attached there by seals 38.

The feed-pipes 34 and pipes 10 are attached near their ends by means of concentric belts or fixation belts 40, the diameter of which are approximately the same as the corresponding crown 26, the section being nevertheless different.

The lower plate 25 rests on six radial arms 42 fixed rigidly to the core 1, and ridged uprights are fixed to their upper and lower ends by rivets, to each crown 26 of the plates 24 and 25.

The resulting structure is particularly rigid, and in the form shown in the drawing, in which the core 1 is vertical, it rests on the plate 25, the weight of which is taken mainly by the arms 42, which include attachment systems 44 for stays 45 fitting-at the upper end through small plates 46, to which they are held by nuts 47.

- These small plates 46 form part of a supporting structure 49, consisting basically of a cylindrical shell 50 with a curvedlower part 51 covering the ends of the pipe sections 10 and a large part of the collecting sphere 17. This lower supporting structure 49 has an inside wall at the top, forming a ring-shaped feed cavity 55, into which leads a fluid feed pipe 56. The shell 50 becomes narrower at the top, forming a cylindrical cover 57 along the central body of the exchanger, at a very short distance from the nest of tubes 59, once formed, and then widens out at the top 58 to form, with an inside wall 60, a ring-shaped enclosure 62 into which leads a discharge pipe 61. Between the nest of tubes and the inner surface of the shell 57 is fitted a deflection device consisting of a thin sheet 64 wound spirally, presenting an edge for attachment 65 along a pipe 10, and another edge 66 resting elastically against the inside surface of the shell 57 or its extension 54. Sheet 64 is thus disposed between the nest of tubes 10 and the inside wall of the cylindrical cover 57. The edges 66 thus rest elastically against the inside surface of the cover 57 to divert the fluid which would otherwise flow in a straight line through the space occupied by sheet 64. Sheet 64 is thus in effect a spiral flow-control vane.

Exchangers of this kind are preferably constructed using the vertical winding technique, which does not form part of the present invention and will not be described in detail. It should be mentioned that the exchangers according to this invention involve a number of lengths of pipe 10a and 10b shaped so that they can be fitted to the spheres 14 or 17, or to the collectors 15 or 19, then fitted into the notches 32, with the seals 38 interposed, in a previously fitted annular crown 26, and then shaped to wind round the core 1, using a mobile platform carrying winders which themselves revolve round the core 1. Round said pipes 10a and 10b (FIG. 1) forming a single layer of turns, two half-crowns are attached to the upper and lower ends to form a lower crown and an upper crown. Ridged uprights 21 are attached directly to the outside of the layer, uniformly round it, and rivetted to the last two crowns thus placed in position. The next layer of pipes can then be wound in the concave spaces formed on said uprights 21 between the projections.

An exchanger of this type can be used for a wide variety of purposes: for instance, a first thermal exchange fluid can be injected into the sphere 13, while a second fluid is conveyed by the collector 15, so that the two fluids move down inside the spiralling pipes 10a and 10b respectively. A third fluid, often in a diphasic form, is injected at the lower end through the feed pipes 56 into the annular cavity 55, separating into a liquid phase and a gaseous phase in the curved wall 51 forming separator below the plate 25. This system of feeding is not covered by the present invention, and will therefore not be described in detail; it will merely be mentioned that gases passing in the feed-pipes 34, leading to the liquid, cause it to rise in the pipes, and possibly draw up vapor, and produces a homogeneous liquid-vapor fluid above the upper plate 25; the fluid thus distributed is directed round the pipes 10a and 10b and reaches the upper annular space 62 from which it is drawn off by the discharge pipe 61.

Instead of this arrangement, it is possible to have an upward movement of the fluids circulating in the pipes 10a and 10b, and a downward movement of an other interstitial fluid, conveyed to the upper end and uniformly distributed, by means of a device not described here.

It will be noted that the exchanger structure described here presents the particular feature that the different i es are firml attached to the core, without being ablr e 0 move eith r axially or radially in relation to it, providing a particularly rigid, sturdy structure, which will not lose its shape and which is therefore easy to transport, and the operating characteristics of which are reproducible. Special features of this structure involve the hermetic devices situated at the notches 32, consisting of tightness joints 38, and the deflection devices between the pipes 59 and the shell 57, consisting of the thin sheet 60; these precautions ensure an even, predictable flow of fluid in the interstitial spaces of the layers of 10a and 10b.

It should be mentioned that the upper and lower plates are of almost the same design. In the case of upward movement in the interstitial fluid, however, the

upper plate does not generally have the feed pipes 34, while keeping the passages 33. In the case of downward movement in this fluid, the lower plate then generally does not have these pipes. The plate may vary accord ing to the direction of the movement of this interstitial fluid.

Exchangers according to the present invention are used for the liquefaction of natural gas.

What is claimed is:

1. In a heat exchanger comprising a central core, an outer covering, a nest of tubes in concentric layers between said central core and outer covering, means for distributing fluid to and collecting fluid from opposite ends of said tubes, and means for directing fluid about the exterior of said tubes; the improvement in which said directing means comprises a plurality of concentric crowns disposed one within the other, each said crown having a cylindrical web and a pair of radially outwardly extending flanges, said flanges having radially outwardly opening notches in which said tubes are disposed.

2. A heat exchanger as claimed in claim 1, the radially outer portion of each flange contacting the radically inner portion of a flange of the next outward crown.

3. A heat exchanger as claimed in claim 1, each of said notches being closed by the next radially outer crown.

4. A heat exchanger as claimed in claim 1, and seals encircling said tubes to close said notches.

5. A heat exchanger as claimed in claim 1, said core being upright, and radial supporting arms for said crowns, said radial arms being rigidly secured to the core.

6. A heat exchanger as claimed in claim 1, and support means for said core.

7. A heat exchanger as claimed in claim 1, and deflection means for fluid outside said tubes, said deflection means extending between said tubes and said outer covering.

8. A heat exchanger as claimed in claim 7, said deflection means comprising a sheet of thin metal the upper edge of which is folded down over a tube in the outermost layer of tubes, the outer edges of said sheet pressing elastically along the inner surface of said outer covering. 

1. In a heat exchanger comprising a central core, an outer covering, a nest of tubes in concentric layers between said central core and outer covering, means for distributing fluid to and collecting fluid from opposite ends of said tubes, and means for directing fluid about the exterior of said tubes; the improvement in which said directing means comprises a plurality of concentric crowns disposed one within the other, each said crown having a cylindrical web and a pair of radially outwardly extending flanges, said flanges having radially outwardly opening notches in which said tubes are disposed.
 2. A heat exchanger as claimed in claim 1, the radially outer portion of each flange contacting the radically inner portion of a flange of the next outward crown.
 3. A heat exchanger as claimed in claim 1, each of said notches being closed by the next radially outer crown.
 4. A heat exchanger as claimed in claim 1, and seals encircling said tubes to close said notches.
 5. A heat exchanger as claimed in claim 1, said core being upright, and radial supporting arms for said crowns, said radial arms being rigidly secured to the core.
 6. A heat exchanger as claimed in claim 1, and support means for said core.
 7. A heat exchanger as claimed in claim 1, and deflection means for fluid outside said tubes, said deflection means extending between said tubes and said outer covering.
 8. A heat exchanger as claimed in claim 7, said deflection means comprising a sheet of thin metal the upper edge of which is folded down over a tube in the outermost layer of tubes, the outer edges of said sheet pressing elastically along the inner surface of said outer covering. 